Same as @RONDAL, ABSOLUTELY do a pre-race warmup for CAT ANYTHING . . .
There’s a great interview with Shaun Stevens, who was the performance coach for Team Sky that you might find useful (scroll down in the link to find the video). While he is describing warming up for time trials (whether short prologues or 50k TT), the same physiological preparations he describes as necessary for time trialing are the same for road racing.
Regarding saddle bags, you should check with the race promoter as to whether they are allowed. During the first early bird crit clinic/race I did where I had my saddle bag on my bike, one of the instructors told me to “loose the bag” prior to the race (it was pretty embarrassing). The two Cat 5 road races I did this year, there were no riders that I could observe that had them. Per advice from our Cat 1 racers, “For Cat 5 racing: carry a tube, tire lever, and CO2 cartridge in your rear center pocket” [I put these in a plastic bag; Cat 1 racers have neutral support and don’t need to carry this stuff]